The invention relates to a travelator, moving ramp or escalator whereby people are transported on a conveyor in a horizontal direction or at an upward/downward angle. The conveyor is mounted on a frame which again is secured to a fixed structure, such as a floor in the case of a travelator, or to different floor levels in the case of a moving ramp or escalator.
As is known for example, from U.S. Pat. No. 4,811,829, the frame of an escalator is usually a rigid trussed construction welded together from beam elements, on which construction the guide tracks and other equipment required for the conveyor are mounted as separate parts. A problem with a frame structure constructed by welding is that it is very difficult to obtain a structure of exact dimensions. The assembly requires the use of expensive and complicated welding jigs. The frame is expensive and producing it is an expensive operation. In simplified terms, the load condition of a frame implemented as a trussed construction corresponds to the load condition of a double-supported beam supported by its ends. According such a frame has been designed to carry, with a certain safety margin, its own weight, the weight of the parts mounted on it and the weight of the passengers, which is why the frame is very heavy and difficult to handle. A trussed construction is usually very stiff and strong, but it is seldom optimized with respect to weight.
Further, European Patent document EP 1 321 424 A1 discloses a frame structure composed of planar frame plate elements. The elements have no profiled parts. The frame plate elements are provided with one or more openings. The openings are formed in the plates by a flame, plasma or laser cutting method. A problem with this frame structure is that its manufacture is time-consuming and expensive.